Lightweight and sporty (currently under 44kg total, including batteries)

Target market is wheelchair users ranging in disabilities from medium level quads with some trunk mobility to weight shift, paraplegics who due to Occupational Overuse Syndrome affecting their upper limb joints from propelling a manual chair need a powered wheelchair, to numerous other disabilities such as MS and CP where trunk movement is possible. However, the more severely disabled wheelchair users would find their inability to weight shift limiting optimising the functions of this wheelchair, but not totally.

Performance and kerb climbing (like a manual chair with a strong user) from a fully electric power wheelchair driven by joystick control.

Uses a rigid sports frame as front frame allowing 24" wheels to be attached reverting it to a sports chair. This potentially allows owners of suitable manual sports chairs to ONLY have to buy the rear power frame containing wheel hub motors, batteries, and controller on the three wheel drivable frame (power unit can be individually driven up ramp into trunk of a car).

High tech, fast charge, NiMH battery pack that is fully sealed and can remain in the chair for transport both in aircraft and cars due to light weight. Can be fast charged and deep cycled without shortening battery life. If needed could be emergency charged to get home from any power outlet via special NiMH solid state charger that weighs less than 1 kg.

New compact, light, hub motors to replace bulky motor/gearbox/wheel combinations. Not only is it more efficient (80%) but aesthetically is a great improvement over the 'heavy' look weight of bulky motors and gearboxes.

Light weight of batteries, motors and frame also improves power to weight ratio reducing power consumption and improving performance and transportability.

Frame tilt feature provides "tilt in space" relax recline without the expense or weight of linear drives to achieve this. Can be driven on level ground while reclined.

The controlled "wheel stand" tilt feature allows the front castors to be clear and above a step and this enables the chair to climb up to 6" steps using mild inertia instead of brute force. This also makes kerb climbs front on safer as situations of one wheel only mounting and tipping the chair are greatly decreased. Wheel's grip to climb step, where often one may climb and the other not can easily tip the chair.

Articulation of frame allows the five wheels to remain in contact with the ground practically all of the time, on dips or mounds. This gives a very smooth ride while still having very little weight on front or rear castors.

Long wheelbase gives less angle of tip for a given obstacle height, like a speed bump and with lighter front castor load, it has similar to a manual chair feel and ride.

Torque from the drive wheels, when going forward, is fully transmitted to the rear stabilising castor, like a kangaroo tail. The only resultant force on the seat frame is forwards, in contrast to normal frame designs where that torque makes them prone to rearward tip-overs.

The lengthening of the frame and wheelbase forward provides a safer, more comfortable ride with improved steering at speed compared to other mid drive wheelchairs with predominantly two very short wheelbases, both front and back.

By lowering the centre of gravity at the same time as stretching the frame, the seat is reclined slightly to a better driving posture and the driver and chair are both made more stable. The lower centre of gravity also greatly decreases sideways tipping risk.

Stretched wheelbase and lower centre of gravity increase safety in a transport mode, such as in a van, where wheelchair and occupant are 'tied down'. Decrease of wheelchair weight also improves safety in that inertia of the wheelchair will be much less, thereby decreasing injury potential in a transport accident.

Mid drive places the drive wheels at the centre of the chair decreasing, if not eliminating the problems of sideways drift when crossing a slope. Also the greater the percentage of weight on the large driven wheels the better the traction and the less the castors will become bogged or affect the ride on minor bumps, troughs or ridges.

In the shortened indoor mode, the rearward tilt is disabled, the seat is more upright, yet there is still some frame movement to allow easy movement up gentle ramps over carpet edges etc. Also loading on front castors is increased and tendency to tip rearwards is decreased by centre of gravity shift.

Turning circle of shortened frame indoor mode is smaller than most manual wheelchairs. Excellent ability to negotiate doorways off corridors and other tight turns due to tapered front and single rear castor.

Transitions between indoor and outdoor modes is by small electric drive motor but is fast - less than 4 seconds operating time.

All controls from the joystick, including chair length switch mean that user can initiate these functions easily.

Visually smaller, with a more open frame and motors in wheels will elicit comments like - "Is that really electric? Where are the motors and batteries?" This makes it psychologically less intimidating for "Joe Public" as their interest in the 'cool' technology often overcomes their fear of the disability. This flows onto the user who finds people, who normally would be intimidated by disability, often start up a conversation asking about the different looking chair. This can break down preconceptions and barriers.

Breaks down into two functional parts and the light weight of those parts enables easier transport, even in domestic car with trunk for power unit, and rear seat commonly the location for folded down seat frame. Also decreases freight costs as total chair would be lighter and less volume packed into a box. Delivery costs can be very expensive for a power chair fully assembled.

Front frames are currently custom built by most manual 'sports' wheelchair manufacturers out of aluminium and often titanium. This customisation provides the user with their preferred body posture, seat size and height. This could enable the rear power unit to be designed with suitable adaptors for a variety of frame brands (within some compatibility restrictions). The rear frame could be standardised to only alter the drive wheel spacing width in say three basic sizes (normal, narrow and child), simplifying manufacture and stock control. This would restrict chair widths for heavy people from using the power unit, thereby self controlling it being overloaded beyond design parameters and test weights.